An Evaluation of Health Service Impacts Consequent to Switching from Brand to Generic Venlafaxine in New Zealand under Conditions of Price Neutrality.

Objective: To study the health impact on adult New Zealand patients who switch from originator brand to generic venlafaxine.

Methods: The national pharmacy database was used to select patients using venlafaxine for at least 6 months. Switchers and nonswitchers were identified, and switch behavior was compared for a 12-month follow-up period. Change in health service use following switching was also compared between switchers and nonswitchers including use of the emergency department, hospital, and specialist outpatient services over the same period.

Results: Approximately 12% of all originator brand users switched to generic venlafaxine, at least half of whom continued to use the generic throughout the follow-up period to August 1, 2012. Almost 60% of new users of the generic venlafaxine, however, switched to using the originator brand. Aside from a slight reduction in the use of outpatient services among switchers, there were no significant differences in health services use between switchers and nonswitchers for either existing or new venlafaxine users.

Conclusions: Although both products remain fully subsidized and available, there is little incentive for prescribers, pharmacists, or patients to switch to the less expensive generic brand. If savings to the national New Zealand budget are to be realized, additional policy measures should be implemented to minimize incentives for multiple and reverse switching, and prescribers, as key opinion leaders, could take the lead in promoting generics to their patients.